The present study is designed for two purposes. The first is the creation of a research paradigm for the study of the personality disorders. This paradigm includes the choice of appropriate comparison groups and the selection of variables to tap a wide variety of relevant areas of psychopathology from the viewpoints of several theoretical perspectives, such as the descriptive-organic and psychodynamic schools. The second purpose is the validation of the Borderline Personality disorder (BPD) and a delineation of its psychopathology in comparison with two other closely allied and already validated disorders: Anti-social Personality (ASP) and Bipolar Type 2 Disorder (BP-2). In order to accomplish this, methods and instruments have been chosen or designed to tap dimensions of mood and impulse pathology, regressive phenomena, difficulties in interpersonal relationships and psychodynamics. Rating procedures have been devised to rate subjects' defense mechanism and conflicts by clinical interview and by projective testing. Initial individual differences across groups will be compared with the results of a two year prospective study of each subject. A study of first degree relatives will also begin during the second year of the project. An attempt will be made to develop a model for each subject group which predicts overall outcome and specific symptomatic and behavioral responses in relation to actual life stressors occuring during the follow-up period.